It is said that in lands with clean air, where the stars fill the sky, there live Ledian in countless numbers. There is a good reason for this—the Pokémon uses the light of the stars as its energy. The spot patterns on its back grow larger or smaller depending on the number of stars in the night sky. When the stars flicker in the night sky, it flutters about, scattering a glowing powder.
Pokédex entry #166
Ledian in Pokémon GO
It's possible to hatch Ledian from an egg?
No, Ledian can't be hatched.
Which are Ledian’s strengths and weaknesses?
Ledian is a bug and flying type Pokémon. bug type pokémons are strong against grass, poison, psychic pokémons but weak against fire, fighting, flying, ghost pokémons. flying type pokémons are strong against grass, fighting, bug pokémons but weak against electric, rock pokémons.